So i'm a guy, and i had sex with my male best friend...kinda

Okay so basically I'm an 18 year old gay male and I've sort of been having sex with my straight best friend of 6 years. Okay so what happens is he'll invite me round to his house to play games and shit, we never usually drink alcohol. It'll get to a point, like 3am where we turn it off and go to bed. He sleeps in his bed and I sleep in the sofa bed. But somehow, during the 1 hour of us talking, I'll end up in his bed, spooning him from behind. We sleep in our boxers so it's pretty much skin on skin apart from the crotch area. We'll be talking and occasionally, he'll either shove his ass further onto my crotch, or I'll thrust on his ass, which obviously gets me hard (He knows I'm gay) and he doesn't mind this as he continues. But then he'll slowly pull his boxers down, as though he doesn't think I notice and then he'll tell me he's not wearing them. So then I'll do the same, so that my dick is against his ass. He'll then end up moving his ass up a little so it's just above and then he'll pull it down so my dick is against his balls. Then he starts using his hands, and due to the amount of pre-cum and lube that he applies, he'll push me in and we start having sex. I cum inside him and then turn over, to which he does the same to me. The difference from most stories is, it's never awkward in the morning, even though we're laid naked next to each other fully aware of what happened. He even kisses me during the sex and in the morning. But then he's convinced he's 100% straight and just trying things out. We've had sex 7 times now, and I don't think he's straight. Should I keep doing this or should I try and get it out of him whether he's straight or not?